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(A) group of scientists is using an Earth-based telescope to study the spots on Ceres and other variations on the dwarf planet's surface. Their results seem to support the idea that sunlight may regularly turn ice into vapor in the Occator crater (where the spots are located).

But, the findings also show that the rate of change from ice to vapor may be irregular, and doesn't match up perfectly with Ceres' day-night cycle. These early findings also indicate that similar observations could be used to study the dwarf planet when the Dawn probe finishes its mission.

Since April 11, instead of photographing the scenery directly beneath it, Dawn has been aiming its camera to the left and forward as it orbits and Ceres rotates. By May 25, it will have mapped most of the globe from that angle. Then it will start all over once more, looking instead to the right and forward from May 27 through July 10. The different perspectives on the terrain make stereo views, which scientists can combine to bring out the full three dimensionality of the alien world. Dawn already accomplished this in its third mapping orbit from four times its current altitude, but now that it is seeing the sights from so much lower, the new topographical map will be even more accurate.

But the recent Ceres news hasn’t just involved Dawn. Paolo Molaro (INAF-Trieste Astronomical Observatory) had led a study looking at the bright spots Dawn found upon approaching Ceres last year. The data Molaro and team drew on came from the European Southern Observatory’s 3.6-meter instrument at La Silla and its HARPS spectrograph, which have shown us not only the motion of the bright spots as Ceres rotates but also variations that indicate volatile material within them. The suggestion is that this material evaporates when exposed to sunlight.

Very interesting. It appears that the bulk of white material is located at the central peak of the crater. Central peaks are formed by the rebounding of the surface after impact much like the surface of water rebounds after a pebble is dropped into a still pond. Other white spots appear near small craters. It could be that the white spots are made of material from deep within Ceres and only erupted onto the surface after an impact and the underground source of the material must have been closer to the surface than average since other craters lack white spots. What I found most interesting is the look of these white spots. No signs that I could see of discoloration due to meteroric dust or other causes. What is needed is a rover to explore and analyze the composition of these spots.

And now, in a study published Wednesday, Dawn scientists have again changed their minds about the nature of Occator’s spots and the implications for Ceres. Based on higher-quality spectroscopic observations taken during Dawn’s descent, Maria Cristina De Sanctis of the National Institute of Astrophysics in Rome and several of her colleagues report in Nature that Occator’s spots are made not of magnesium sulfate, but of a very different salt—sodium carbonate.

As opposed to the Moon and Mercury (which, like Ceres, have a very small spin axis tilt, or obliquity), the cold trap regions on Ceres extend much further toward the equator. The permanently shadowed regions have to be close to the poles on the Moon and Mercury to get cold enough for ice to remain stable. But like Mercury, these areas account for about the same fraction — less than one percent — of the surface area of the northern hemisphere, and most of these areas on Ceres are cold enough to serve as efficient cold traps for water ice.

Their work suggests that Ceres is only partially differentiated, with a core made of rock overlaid by a shell composed of a mix of icy, salty and rocky material that is about 43.5 to 120 miles (70 to 190 km) thick.

"The partial differentiation suggests that Ceres was hot at one point, but it did not fully separate the water and other volatiles from its rocky components," study lead author Ryan Park, a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, told Space.com.

So if Ceres has warm spots, even beneath the surface, it might explain the bright spots as being evidence of geyers or cryovolcanism as conventional wisdom supposes they are made up of high-albedo salts scattered from Ceres's interior.

"We have found that the divisions between different layers are less pronounced inside Ceres than the Moon and other planets in our Solar System," Ryan Park, from NASA’s Jet Propulsion Laboratory, said in a statement. "Earth, with its metallic core, semi-fluid mantle and outer crust, has a more clearly defined structure than Ceres."

Dawn was able to prove that Ahuna Mons must have had another outburst recently, as in this year. Its VIR (visible and infrared mapping spectrometer) was able to detect light wavelengths that suggested water ice in one of Ceres’ craters. Strangely enough, exposed water ice visible to the robotic eyeball is rare, even though the planetoid’s crust is a glacial layer of water ice and silicates over what scientists think could be a freezing ocean of liquid water at its core. If it exists, that could be where all the slushy vomitus is coming from, much like how how the gushing spectacle of magma arises from Earth’s liquid inner layers. Terrestrial volcanoes have been crucial to scientists’ understanding of the extraterrestrial.

That ice was seen in just one of the craters the researchers looked at "is surprising," Platz told Space.com. One possibility is that cosmic impacts may have masked the ice in other craters with dust, he said. Another possibility is that the axial tilt of Ceres may vary over very long periods of time (even though it appears steady now), therefore exposing craters to sunlight that could destroy the water ice, he added.

Perhaps the best-known area on Ceres is the 57-mile-wide (92 kilometers) crater Occator, where scientists have discovered the source of the bright spots as highly reflective salts. "The question is, where is the material in this impact coming from?" said Ralph Jaumann, a planetary scientist at the German Aerospace Center. He speculates that the impact that created the crater could have triggered an upwelling of a briny liquid from inside Ceres, which flowed out, froze and then vaporized, leaving behind the salts.

“Models of Ceres based on data collected by NASA’s Dawn spacecraft plus ground-based telescopes indicated substantial amounts of water- and carbon-bearing minerals such as clays and carbonates,” explains Vernazza. “Only the mid-infrared observations made using SOFIA were able to show that both silicate and carbonate materials are present on the surface of Ceres.”

Dawn’s primary objective in this sixth orbital phase at Ceres (known as extended mission orbit 3, XMO3 or "this sixth orbital phase at Ceres") is to record cosmic rays. Doing so will allow scientists to remove that "noise" from the nuclear radiation measurements performed during the eight months Dawn operated in a low, tight orbit around Ceres. The result will be a cleaner signal, revealing even more about the atomic constituents down to about a yard (meter) underground. As we will see below, in addition to this ongoing investigation, soon the adventurer will begin pursuing a new objective in its exploration of Ceres.

Aliphatic organic compounds - carbon-based building blocks that may have a role in the chemistry that creates life - have been detected for the first time on Ceres, an asteroid and dwarf planet, a new study reveals. What's more, the data indicate that the organic material formed on the asteroid itself, rather than being deposited from another source. Here, Maria Cristina De Sanctis and colleagues used the Visible and InfraRed Mapping Spectrometer on the Dawn spacecraft to observe Ceres' surface near a crater called Ernutet. The instrument detected absorption at wavelengths that are characteristic of the methyl and methylene groups present in aliphatic organic matter. Although the data are not sufficient to determine the exact molecular compounds present, they match tar-like minerals such as kerite or asphaltite. These compounds are unlikely to have been delivered from an exterior source in an impact, the authors say, because the extreme heat from an impact would have destroyed these types of compounds, and also, the surface distribution is not what would be expected should their source be an external body. Because Ceres hosts large quantities of water and may have retained internal heat from its formation period, these organic compounds probably developed within the planetary body. In a related Perspective, Michael Küppers discusses recent discoveries of water and complex molecules on Ceres.

Scientists under the leadership of the Max Planck Institute for Solar System Research (MPS) have now for the first time determined the age of this bright material, which consists mainly of deposits of special mineral salts. With about four million years only, these deposits are about 30 million years younger than the crater itself.

Because of this evidence for abundant ice, many scientists think that Ceres' exosphere is created in a process similar to what occurs on comets, even though they are much smaller. In that model, the closer Ceres gets to the sun, the more water vapor is released because of ice sublimating near or at the surface.

“Landslides cover more area in the poles than at the equator, but most surface processes generally don’t care about latitude,” said Schmidt, a faculty member in the School of Earth and Atmospheric Sciences. “That’s one reason why we think it’s ice affecting the flow processes. There’s no other good way to explain why the poles have huge, thick landslides; mid-latitudes have a mixture of sheeted and thick landslides; and low latitudes have just a few.”

A new movie shows these opposition images, with contrast enhanced to highlight brightness differences. The bright spots of Occator stand out particularly well on an otherwise relatively bland surface. Dawn took these images from an altitude of about 12,000 miles (20,000 kilometers).

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